[vlc-devel] [PATCH] input: add ES_OUT_FORCE_PACE_CONTROL request

Rémi Denis-Courmont remi at remlab.net
Tue Oct 30 17:05:40 CET 2012

Le mardi 30 octobre 2012 17:54:41, Frédéric Yhuel a écrit :
> When the input does have some sort of pace control, but would send a
> bunch of samples to the decoder within a short period of time.

If the input has pace control, then the ES output is paced and your patch 
should have no effects. If the input has uncontrolled pace, then your patch 
will break buffering.

> For example the input sends 3 seconds worth of samples to the decoder
> within 10 ms, then again 3 seconds later, etc...
> Does it make sense?

No. The problem is equally valid for any input without pace control even if it 
is bursty.

> With my new Smooth Streaming module, the patch works well, with a low
> bandwidth server, and with a local server as well.

It might seem to work in short time frames. It might even seem to fix playback 
of very bursty inputs. But unless the server clock is synchronized with the 
client clock (which is unlikely unless it is localhost), there will be long 
term drift. Over time, that will result in buffer overflow or underflow, and the 
consequences will not be good.

In your particular case, overflow would probably strike the stream_Demux FIFO, 
delaying the playback more and more, until VLC runs out of memory.

Rémi Denis-Courmont

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